WS-H+ preparation
To enhance the electrical power generation from the WS-WEG, the WS was further treated in acid solutions containing Hydrochloric Acid (3 M) 40% vol, Sulfuric Acid (3 M) 30% vol, and Nitric Acid (3M) 30% vol. After freeze drying at -12 °C for 12 h, and cleaning with DI water a nano-engineered WS was formed, which was designated as WS-H+. The WS-H+ samples were subsequently put independently on reservoirs holding neutral solutions (pH 6.9) and alkaline solutions (pH 12.5) with NaOH of 80% (v/v) and NaCl of 20% (v/v).